The abuse of phenethylamine and tryptamine based hallucinogenic drugs continues to be a serious problem that is now rivaled by the appearance of numerous cannabinoid agonists and cathinones (bath salts). Data from the DEA has show the appearance of novel hallucinogenic phenethylamines and tryptamines either previously encountered in insignificant amounts or not seen at all. This is due in part to the publication of cookbook chemical syntheses and detailed accounts of the doses used and hallucinogenic effects seen in humans for almost all of the 179 phenethylamine and 53 tryptamine analogs that were synthesized and self-administered by A. T. Shulgin and his associates during more than 30 years. This information has been widely disseminated via the Internet. These are disturbing developments that substantially aid and encourage clandestine drug production and may presage a resurgence in phenethylamine and tryptamine abuse and exacerbating the overall problems of hallucinogenic drug abuse. We have begun a program to synthesize and evaluate a number of these hallucinogenic agents and their antagonists. MDPV (3,4-methylenedioxypyrovalerone) is a widely abused psychomotor stimulant with dangerous side effects that is about 10 times as potent as cocaine in rats. We recently studied the metabolism of racemic 3,4-MDPV and developed methodology to quantify MDPV and its primary metabolites 3,4-catechol-PV and 4-OH-3-MeO-PV in plasma. The method employs liquid chromatography-high resolution mass spectrometry and affords good selectivity and sensitivity.